Pressure-sensitive adhesive sheets for a tire referred to as tire display labels and the like are conventionally known. To inform customers of tire information and stimulate consumer demand, such adhesive sheets include a tire display part including information such as the tire manufacturer and brand names, the tire size (width, flat ratio, and rim ratio), and warnings relating to tire use, and are used for adhering onto an area of the tire including the tread surface. That is, a pressure-sensitive adhesive sheet for a tire is normally constructed of a film with a deposited aluminum layer as a substrate, and an adhesive layer that has a rubber resin or an acrylate alkyl ester resin as a main component being formed in a layer on the substrate.
A pressure-sensitive adhesive sheet for a tire has been disclosed that uses a white-colored film as the surface material. Such white-colored film uses a polypropylene resin as a surface substrate, includes internal voids, and is composed of three or more biaxial stretching films, and includes an adhesive layer that has a predetermined adhesion for the white-colored film and is mainly composed of a cross-linked acrylate alkyl ester resin (refer, for example, Patent Document 1).
Also, a pressure-sensitive adhesive sheet for a tire that includes an anchor coat layer, a layer of a polyvinylidene chloride-vinyl chloride copolymer, and an adhesive layer having a predetermined adhesion to the surface of a polypropylene film including a white pigment, has been disclosed (refer, for example, Patent Document 2).
Moreover, a pressure-sensitive adhesive sheet for a tire having an adhesive layer that includes a predetermined amount of natural rubber, an ABA-type block copolymer, and a tackifier, has been disclosed (refer, for example, Patent Document 3).
However, extremely large convexes and concaves are formed on the tread surface of a tire, and due to the air vent holes in a mold which is used when molding a tire, whisker-like projections called “spews” are formed on the tire, which makes it difficult for a pressure-sensitive adhesive sheet for a tire to accurately adhere to the tire. In addition, not a small amount of the mold releasing agent which is used when manufacturing tires is transferred and adheres to the surface of the tire, so that the problem of pressure-sensitive adhesive sheets for a tire that have been adhered to the tire being susceptible to peeling off during storage and transportation of the tires has been observed. In particular, during winter season when the external air temperature falls to around 5° C., for example, the adhesion correspondingly decreases and the adhesive sheets becomes to be peeled off. When the pressure-sensitive adhesive sheets for a tire are adhered to studless tires, the surface of the tire has a special convex/concave pattern and contains special additives, so that the adhesion to such tires becomes low and the peeling off of the pressure-sensitive adhesive sheets during the storage and transportation of tires, has been especially observed.
In addition, with the conventional pressure-sensitive adhesive sheets for a tire described above, when anyone of the described adhesive layers is provided, an application process is carried out by using a solvent which is then removed by a drying process, but this results in the problems of an increase in the scale of the manufacturing process, an increase in the manufacturing time, and insufficient consideration of environmental matters (refer Patent Documents 1 to 3). In particular, when a polyvinylidene chloride-vinyl chloride copolymer is provided as even just part of a pressure-sensitive adhesive sheet for a tire (refer Patent Document 2, for example), the environmental problem of the likely emission of dioxin during incineration of the tire has been observed.    Patent Document 1:JP10-147757A    Patent Document 2:JP2002-294187A    Patent Document 3:JP11-80690A
Thus, by carrying out careful research, the inventors of the present invention have discovered that by using a pressure-sensitive adhesive sheet for a tire that uses a hot melt-type adhesive composition having the special adhesive characteristics (loop tack adhesion), it is possible to easily solve the problem of pressure-sensitive adhesive sheets for a tire in peeling off during the storage and transportation of tires.
That is, it is an object of the present invention to provide a pressure-sensitive adhesive sheet for a tire and a method for manufacturing the same, where the pressure-sensitive adhesive sheet for a tire has a strong adhesion for a tire even at low temperature, can strongly adhere to a studless tire, and whose characteristics do not greatly deteriorate at high temperature.